JP2010133042A - Splittable conjugate fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a splittable conjugate fiber easily splittable at a final step while keeping the fiber shape in a midway step of post processing. <P>SOLUTION: In the splittable conjugate fiber, at least one component in two or more kinds of fiber-forming components constituting the splittable conjugate fiber contains a polyamide-based polymer (A) 1 as a main component, and at least one component in the two or more kinds of the fiber-forming components contains a modified polyester component (a) having a sulfonate group, and a polyalkylene glycol component (b). Preferably, the modified polyester component (a) is present in the polyamide-based polymer by being dispersed as a melt or particles, the fiber-forming components constituting the splittable conjugate fiber are the polyamide-based polymer (A) 1 and a polyester-based polymer (B) 2, and the polyester-based polymer (B) 2 contains the modified polyester component (a) having the sulfonate group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a split type composite fiber composed of two or more types of fiber-forming polymers. More specifically, the present invention relates to a split-type composite fiber that can be easily split in the final process while maintaining the fiber shape in the middle of post-processing, and more particularly, to a split-type composite fiber that is optimal for use in ultrafine fiber base materials for artificial leather. Is.

  Conventionally, fabrics that are excellent in quality and fine and have fine touch and drape properties have been put on the market, and ultrafine fibers are often used to obtain such fabrics. As a means for obtaining ultrafine fibers, there is a method of producing fine fibers from the beginning, but in order to produce more efficiently, many obtain composite fibers from different polymers of two or more components and obtain the fibers. A method is mainly employed in which the obtained fiber is divided and refined through processes such as extraction and extraction. In order to be superior in terms of process rationalization and process tone, a method is used in which a composite fiber that can be made into ultrafine fibers is manufactured in advance and made into a fabric, and then the fibers are thinned.

  For example, Patent Document 1 discloses that a split-type composite fiber is divided into ultrafine fibers by applying a high-pressure membrane-like water stream to a long-fiber nonwoven fabric made of split-type composite fibers that do not require extraction equipment and an extraction process. There has been proposed a method for obtaining a bulky nonwoven fabric composed of ultrafine fibers that are not substantially three-dimensionally entangled. However, there is a problem that it is difficult to obtain three-dimensional entanglement, although the degree of fiber separation can be increased by the method of applying this high-pressure membrane water flow.

  Further, Patent Document 2 proposes a multi-divided hollow fiber having a hollow ratio of 25% or more and discontinuous divided holes in the fiber axis direction so that the division is more likely to occur. However, in such a split type fiber having a high hollow ratio and discontinuous split holes, there is a problem that halfway splitting is likely to occur in the middle of post-processing and the quality is not stable.

In particular, in the production of a nonwoven fabric composed of ultrafine fibers, in order to ensure the strength of the nonwoven fabric, a method of dividing the composite fiber into a nonwoven fabric through an entanglement process first and then dividing it into ultrafine fibers is essential. Otherwise, the fibers will be cut at the time of entanglement, and sufficient strength cannot be obtained, or the cut ends of the fibers will be scattered, resulting in a problem that the process environment is deteriorated and the quality of the nonwoven fabric is adversely affected. In addition, when undivided fibers remain in the high-density ultrafine nonwoven fabric, there is a problem in that the flexibility and workability of the artificial leather are adversely affected.
That is, a fiber that is not divided at the time of entanglement and that can be easily divided at the time of the division process after entanglement has been demanded.

  However, with conventional split fibers, the mechanically strong treatment that sufficiently entangles is liable to be damaged during entanglement, and conversely, with split split fibers that do not split during entanglement, subsequent split processing does not occur. Therefore, there has been a demand for a split type composite fiber that can achieve both splitting property and confounding property.

JP-A-4-30031 JP 2000-17519 A

  The present invention has been made against the background of the above-described prior art, and an object of the present invention is to provide a split-type composite fiber that can be easily split in the final process while maintaining the fiber shape in the intermediate process of post-processing.

  In the split-type conjugate fiber of the present invention, at least one component of two or more types of fiber-forming components constituting the split-type conjugate fiber is mainly composed of a polyamide-based polymer (A), and at least of two or more types of the fiber-forming components. One component contains a modified polyester component (a) having a sulfonate group and a polyalkylene glycol component (b). Furthermore, the modified polyester component (a) is present in the polyamide polymer (A) in a dispersed state as a melt or granule, or the polyamide polymer (A) is mixed with the modified polyester component (a). The total amount of the polyalkylene glycol component (b) is preferably 3 to 20% by weight, and the fiber-forming component constituting the split-type composite fiber is composed of a polyamide polymer (A) and a polyester polymer ( It is preferable that the polyester polymer (B) is a modified polyester component (a) having a sulfonate group. Moreover, it is preferable that the fineness of a split type composite fiber is 0.15-10 dtex, and the fineness of each fiber moldability component which comprises a split type composite fiber is 0.01-0.35 dtex.

  Another method for producing an ultra-fine fiber nonwoven fabric of the present invention is characterized in that the above-mentioned split type composite fiber of the present invention is entangled and divided. Furthermore, the manufacturing method of the base material for artificial leather is characterized by impregnating an ultrafine fiber nonwoven fabric obtained by entangling and dividing the split type composite fiber of the present invention with a polymer elastic body.

  ADVANTAGE OF THE INVENTION According to this invention, the split type composite fiber which can be divided | segmented easily in the final process is provided, maintaining a fiber shape in the middle process of post-processing.

  In the split-type conjugate fiber of the present invention, it is essential that at least one component of two or more fiber-forming components constituting the split-type conjugate fiber is mainly composed of the polyamide polymer (A). Here, the two or more types of fiber moldable components are selected from two or more types of fiber moldable polymers that are usually incompatible with each other. And the split type composite fiber of this invention can form an ultrafine fiber, when fiber moldability components divide | segment at a subsequent process.

  The two or more types of fiber-forming components are not particularly limited as long as they are generally high-molecular polymers having fiber formability, and are not particularly limited as long as they have a separating ability to separate between components by mechanical treatment. . Of these, the combination of the polyamide polymer (A) and the polyester polymer (B) is preferred as the combination of the fiber moldability components because of high industrial productivity and performance.

Examples of the polyamide polymer (A) essential in the present invention include nylon-6, nylon-66, nylon-610, nylon-11, nylon-12 and the like.
On the other hand, examples of the polyester polymer (B), which is another component preferably used, include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and copolyesters containing these as main components. In particular, in nonwoven fabrics that require denseness, such as nonwoven fabrics for artificial leather bases, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate having heat shrinkage are the main components in order to impart heat shrinkability. It is preferable to use a copolyester. Among these, as a combination of polymer components, a combination of nylon-6 / polyethylene terephthalate is preferable from the viewpoints of production stability and cost.

  In the present invention, it is essential that at least one of the two or more fiber moldable components contains a modified polyester component (a) having a sulfonate group and a polyalkylene glycol component (b). Furthermore, it is preferable that the modified polyester component (a) is contained in the polyamide polymer (A). As the contained state, the modified polyester component (a) is melted in the polyamide polymer (A). Or it is preferable that it exists as a granular material.

  The modified polyester component (a) used in the present invention has an aromatic polyester or aliphatic polyester such as polyethylene terephthalate or polybutylene terephthalate as a main skeleton. And as a sulfonate group couple | bonded with the main skeleton, an isophthalic acid sulfonate group is preferable. Furthermore, it is preferably a polyester in which an isophthalic acid sulfonate metal salt, a dicarbonate component, and an oxyalkylene glycol component are copolymerized. Among them, 5-sodium sulfoisophthalic acid is preferable as the isophthalic acid sulfonate metal salt, and terephthalic acid or isophthalic acid is preferable as the dicarbonate component.

  The isophthalic acid sulfonate group used here is preferably copolymerized with a dicarbonate component, and the amount of copolymerization is preferably 0.1 to 30 mol%, and more preferably 2 to 20 mol%. preferable. Moreover, as an oxyalkylene glycol component preferably used, ethylene glycol, trimethylene glycol, tetramethylene glycol and the like are preferable. The glycol component is particularly preferably a copolymer of a polyalkylene glycol component. The number average molecular weight of the polyalkylene glycol component is preferably 1,000 to 500,000, more preferably 2,000 to 10,000, and specifically preferably polyoxyethylene glycol. The copolymerization amount of the polyalkylene glycol component is preferably 30 to 90% by weight, more preferably 40 to 80% by weight, based on the polyester composed of the dicarbonate component and the alkylene glycol component.

  On the other hand, in the present invention, it is essential that at least one polymer component contains the polyalkylene glycol component (b) together with the modified polyester component (a). As the polyalkylene glycol component (b), polyoxyalkylene glycol is preferable, and polyethylene glycol is particularly preferable. The number average molecular weight is preferably 1,000 to 500,000, and more preferably 2,000 to 10,000 is effective for spinning stability.

  The present inventors constituted a fiber by using together a modified polyester (a) having a sulfonate group which is a polar group, as compared with the case where the polyalkylene glycol component (b) or the like is contained alone as conventionally thought. Surprisingly, it has been found that the interfacial peeling between the fiber-forming polymer components after spinning is remarkably facilitated even if the spinnability of the composite fiber remains high. Is. Even when the modified polyester component (a) and the polyalkylene glycol component (b) are used in combination, the cross-sectional shape of the composite fiber is less likely to change over time, and can be produced stably. It was found that the degree of division hardly varies.

  The addition of polyalkylene glycols not only improves the splitting property but also has the effect of suppressing the generation of static electricity caused by friction between fibers in the spinning process, which is preferable for ensuring the stability of the spinning process. For example, when the split-type composite fiber of the present invention is made into a long-fiber nonwoven fabric, the split-type composite fiber is collected on the net, or the long fiber or the short fiber aggregate in which the spun long fiber is unwound on the net In processes such as collecting on the body, static electricity is often generated due to friction between fibers. When passing through such a process, addition of polyalkylene glycols is particularly preferable for suppressing the generation of static electricity and ensuring the stability of the spinning process.

  Here, it is preferable that the addition amount of a modified polyester component (a) and a polyalkylene glycol component (b) is 3-20 weight part with respect to the fiber-forming polymer added in total. When the amount exceeds 20 parts by weight, the spinnability is deteriorated, the melt viscosity of the fiber-forming polymer is greatly reduced, and the formability control of the cross-sectional shape of the peelable split-type fiber tends to be difficult. On the other hand, when the amount is less than 3 parts by weight, the effect of improving the splitting property tends to decrease.

  Furthermore, the ratio of the added amount of the modified polyester component (a) and the polyalkylene glycol component (b) is such that the weight of the modified polyester component (a) is 0.1 to 10 times the weight of the polyalkylene glycol component (b). It is preferable that it is in the range, and it is particularly preferable that the weight ratio is 2 to 6 times.

  As a method for adding the modified polyester component (a) and polyalkylene glycol component (b), which are essential in the present invention, to the fiber-forming polymer, any method can be employed. For example, a method of adding in the polymerization step of the fiber-forming polymer, and a mixture of the fiber-forming polymer, the modified polyester component (a) and the polyalkylene glycol component (b) was mixed when the composite fiber was melt-spun. Various methods such as a method of subsequent melt-kneading, a method of melting the fiber-forming polymer and a mixture of the modified polyester component (a) and the polyalkylene glycol component (b) separately and mixing them immediately before melt spinning are adopted. Can be done. In particular, a method in which a granular mixture of a modified polyester component (a) and a polyalkylene glycol component (b), which have been previously melt-kneaded and molded, and a fiber-forming polymer resin are mixed and melt-spun is particularly preferred. It is also possible to avoid adverse effects due to the heat resistance of the kind, and the melt spinning work becomes easy. As another method, a melted mixture of the modified polyester component (a) and the polyalkylene glycol component (b) is weighed, fed into an extruder for melting a fiber-forming polymer, or supplied to an outlet, and mixed with a static mixer. Can also be mentioned as a preferred method.

  And as the composite form of the split-type conjugate fiber of the present invention, it is a fiber composed of two or more types of fiber-forming polymers, and at least a part of the joining interface of each polymer has reached the fiber cross-section circumference, It is preferable to be in the form of a peelable split composite fiber that can be split into each component by mechanical treatment or the like. In addition, it is desirable from the viewpoint of the separation property that one component is divided into a predetermined number by the other component. Among these, a cross-sectional shape in which one component is arranged radially between other components is preferable. Such a composite form is obtained by composite spinning of two types of fiber-forming polymers using a known composite spinneret.

  In particular, the split-type composite fiber of the present invention is composed of two components that are alternately adjacent as shown in FIG. 1, and the modified polyester component is present in the form of a melt or granule dispersed in the polyamide polymer interface and inside the polymer. It is preferable.

  The fineness before splitting of the split composite fiber of the present invention is suitably in the range of 0.15 to 10 dtex, and more preferably in the range of 2 to 5 dtex. If it is too thin, the productivity tends to be low, and if it is too high, it tends to be difficult to make ultrafine fibers even if it is divided. The fineness after division is preferably in the range of 0.01 to 0.35 dtex. The fineness after splitting of the split-type conjugate fiber of the present invention is preferably as thin as possible, but if it is too thin, it tends to be difficult to ensure production stability. In addition, when the fineness is too high, it is difficult to secure a flexible texture peculiar to ultrafine fibers.

  Therefore, the number of divisions of the split composite fiber of the present invention is preferably 4 to 48, and particularly preferably 8 to 24 from the balance between the fineness of the ultrafine fiber after splitting and the ease of splitting. The volume ratio of each fiber-forming polymer constituting each divided ultrafine fiber is preferably in the range of 20:80 to 80:20, and particularly preferably in the range of 40:60 to 60:40. By changing the division ratio, it is possible to adjust the division property and strength.

  Furthermore, it is preferable that at least one of these divided ultrafine fibers is heat shrinkable. In order to impart heat shrinkability, for example, the spinning speed and the draw ratio after spinning, the drawing temperature, in the case of direct-spun type non-woven fabric, the temperature at the time of thinning by an air soccer or ejector used for pulling the fiber, the air pressure Can be obtained by adjusting.

  Another manufacturing method of the ultrafine fiber nonwoven fabric of the present invention is a manufacturing method which essentially requires entanglement and splitting of the split type composite fiber of the present invention as described above. Furthermore, as a method of entanglement, it is preferable to use a needle punch.

  For example, the above-mentioned split type composite fiber is spun-bonded, which is a typical spinning direct-bonding type non-woven fabric molding method, or is collected while being spun and stretched and wound up once with a high-speed traction fluid. It is also a preferable aspect to directly form the web by a known method such as collecting the web on the surface.

More specifically, the split type composite fibers extruded from the spinning machine can be drawn by an ejector and collected on a moving net to form a web. The basis weight of the fiber aggregate can be determined by the amount of collected by spinning fibers weight and net speed, it is preferable that the basis weight of ^{20g / m 2 ~60g / m 2} . If the basis weight is too large, the basis weight variation tends to increase in the next lamination step. On the other hand, if the amount is too small, the production efficiency of the laminating process is lowered and uniform lamination tends to be difficult.

  The thus obtained long fiber web composed of the split composite fibers of the present invention is laminated in a plurality of pieces as necessary, or alone, preliminarily heat-bonded as necessary, and once wound up. It is preferable that a fiber structure such as a long-fiber nonwoven fabric is obtained by performing a confounding process such as a needle punch process or a high-pressure water flow after or continuously. In the lamination process, a known cross layer can be used.

  The split-type conjugate fiber of the present invention is suitable for a production method in which the fiber composite that has passed through the post-processing step as described above is further processed to make a split ultrafine. Since the split-type composite fiber of the present invention can be split ultrathinned at a stretch by a certain impact or the like, it does not cause ultrathinning until it becomes a fiber composite, and the processability is kept high. It became possible to obtain high-quality products by proceeding with division and miniaturization at once in the process.

  Such a dividing method is preferably a mechanical dividing process. The mechanical division is division using mechanical force such as vibration, hitting, and shearing. Since there is a difference in the easiness of division depending on the type and production method of the bonded fibers, it is preferable to use a division method that combines vibration and shear based on tapping. In particular, when a striking-type splitting process is performed, a shearing force can be efficiently applied in the thickness direction of the sheet, and split-type composite fibers can be split into ultrafine fibers efficiently. As equipment capable of performing the striking-type division process, a commercially available striking-type grinder for leather can be used. Furthermore, as a method of more completely dividing, it is preferable to immerse the non-woven fabric before the division in an aqueous surfactant solution in advance and then divide it by mechanical stress.

  In the split type composite fiber of the present invention, the modified polyester component (a) bleeds out at the interface between the two component polymer components in the spinning process, and it is considered that a large amount exists between the two components, and the peelability is improved. .

  It is preferable that the nonwoven fabric after the split-type composite fiber to be formed is divided into ultrafine fibers is then subjected to shrinkage treatment in hot water. At this time, the area shrinkage rate of the nonwoven fabric can be arbitrarily changed depending on the shrinkage rate of the fibers, the constituent ratio of the shrinkage fibers, and the degree of entanglement. However, when the base material is used for artificial leather, the shrinkage rate is 15 to 60. % Is preferred. More preferably, it is 25 to 45%. If the shrinkage rate is less than 15%, it is difficult to obtain a high-density nonwoven fabric even if the fiber of the present invention is used. If the shrinkage rate exceeds 60%, the fiber becomes too dense and the degree of freedom of the fiber is lost. The resulting artificial leather is hard and unfavorable.

Here area before shrinkage and the area shrinkage say the S _1, if the area after shrinkage was S _2, are extracted by the following calculation.
Shrinkage rate (%) = (S ₁ −S ₂ ) × 100 / S ₁

  The temperature of hot water is preferably 65 to 75 ° C. because of its efficiency. When the temperature is 65 ° C. or lower, in most cases, shrinkage does not occur, and when the temperature is 75 ° C. or higher, energy loss due to evaporation is large. Depending on the degree of thermal shrinkage of the nonwoven fabric, in most cases, it is preferable to complete the shrinkage in about 30 to 60 seconds. In order to uniformly shrink these non-woven fabrics, a state of swimming in hot water using buoyancy is preferable. The shrinked nonwoven fabric is preferably dehydrated and then dried with hot air to obtain a high density ultrafine fiber nonwoven fabric.

Moreover, when using this nonwoven fabric as a base material for artificial leather, the density of the nonwoven fabric before division | segmentation ultrathinning is 0.10-0.30g / cm < ³ >, the division | segmentation extrafineness, the artificial leather base after a hot-water contraction process It is preferable that the apparent density of the material is 0.15 to 0.55 g / cm ³ .

  In addition, the above-described split type composite fiber of the present invention can be entangled and split, and an artificial leather can be produced by impregnating and solidifying a polymer elastic body. As the polymer elastic body, those used in conventionally known artificial leather can be used. For example, water-based or solvent-based polyurethane is preferably used. Furthermore, when solvent-based polyurethane is used, it is preferable that the polymer elastic body obtained by coagulating a dimethylformamide solution of polyurethane by a wet coagulation method is porous coagulated. Furthermore, it is also preferable to use a surface-like artificial leather after drying by surface raising or dyeing, or to form a silver-like artificial leather by forming a colored film of a polymer elastic body such as polyurethane on the surface.

  In the nonwoven fabric and artificial leather obtained using the split type composite fiber of the present invention, the fiber bundle at the time of entanglement is broken, and unlike the conventional nonwoven fabric composed of simple thin fibers, the thin fibers after splitting are alternately intertwined. When it is used as artificial leather with a silver tone, it does not generate large deep wrinkles even when it is folded inward or outward, and it becomes wrinkles that are finely dispersed on the surface. Will not remain.

  Since the split type composite fiber of the present invention as described above has excellent processability and can finally form ultrafine fibers with a high split rate, it can be applied to products with excellent quality. For example, artificial leather includes sports shoes, shoes for women's and men's shoes, various ball applications, industrial materials such as furniture / vehicles, interior materials, interior materials, bookbinding for notebooks and notebooks, clothing, etc. It can be preferably used for the use. In addition to artificial leather, it can be used for clothing, interior materials, interior materials, industrial materials, wipers such as industrial wipers and wiping cloth, bag filters, filter cloths, and other medical hygiene materials. It can use preferably also for each use of these.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an Example are a basis of weight, and each measured value was calculated | required according to the following method, respectively, and unless otherwise indicated, a measured value measured 5 points | pieces. The average value.

(1) Initial split ratio, split ratio after time The split ratio of the peelable split type composite fiber constituting the nonwoven fabric was obtained by photographing the cross section of the nonwoven fabric after splitting with an electron microscope at a magnification of 200 times. Measurement was made by dividing the difference in cross-sectional area between the entire area and the undivided filament (including those that were not completely divided, for example, those divided into about 2 or 3 pieces). The larger the division ratio, the better the division. The sample after 4 hours from the start of adding the modified polyester component and polyalkylene glycol component to the fiber-forming polymer component is “initial”, and the sample after 30 hours is “after time” It was. In addition, the division | segmentation process was laminated | stacked and entangled after web formation, and was implemented immediately (within 1 hour).

(2) Variation of division ratio When obtaining the initial division ratio, samples of 5 points in the width direction of the nonwoven fabric and 4 points in the traveling direction were collected, and the maximum value Max, the minimum value Min, and the average value Ave of the division ratio were obtained by the above method. And determined by the following formula.
Variation in division ratio (%) = {(Max−Min) / (2 · Ave)} · 100

(3) Fineness of ultrafine fiber The fineness of the undivided composite fiber was measured with a fineness measuring device (manufactured by SERCH Co. LTD, model DC-21) at a test length of 2.5 cm and a load of 1 g. It was determined by dividing by the number of fiber-forming polymers (number of divisions) existing in a mutually independent form within a cross section perpendicular to the fiber axis.

(4) Texture of nonwoven fabric Sensory evaluation of softness and tactile sensation by five evaluators was performed in five stages, and the average value was evaluated. It shows that it is so favorable that a number is large.

(5) Bending resistance (flexibility) of artificial leather
The bending resistance (flexibility), which is an important quality of artificial leather, was evaluated by measuring the bending resistance of an artificial leather base material impregnated and solidified with an impregnation solution. That is, a flexible test piece 25 mm × 90 mm is prepared, and the lower 20 mm in the longitudinal direction is vertically held by a holder, and the other end of the test piece is placed on the U gauge measuring part at a height of 20 mm from the holder. While holding the test piece so that it hits the center at a position of 20 mm from the tip of one end of the sheet, the holder was slid and fixed, and after 5 minutes, the stress was read from a recorder, The degree of flexibility was converted to stress.

[Example 1]
As the modified polyester (a), a sulfonic acid group-containing modified polyester copolymer (a1) comprising 17 parts by weight of terephthalic acid, 3 parts by weight of sodium 5-sulfoisophthalate, 5 parts by weight of ethylene glycol, and 75 parts by weight of polyethylene glycol having a molecular weight of 4000. ) Was melted at 130 ° C. under vacuum, and polyethylene glycol (b1) having a molecular weight of about 19000 was added as polyalkylene glycol (b) to form a pellet. At that time, the mixing ratio of the modified polyester (a) and the polyalkylene glycol (b) was (a) :( b) = 4: 1.

  Nylon-6 (Intrinsic viscosity 1.2 in 98% concentrated sulfuric acid) (A) dried at 120 ° C. is fed to the extruder, and the above-mentioned (a1) and (b1) are placed in front of the extruder inlet on the nylon-6 side. A 4: 1 mixture and nylon-6 (A) were mixed, added to nylon-6 so as to be 5 wt%, and both were melted at 245 ° C. Separately dried at 140 ° C., polyethylene terephthalate (intrinsic viscosity 0.62 in o-chlorophenol) (B) copolymerized with 10 mol% of isophthalic acid was melted at 265 ° C. with an extruder different from the above. . Subsequently, the nylon-6 mixture melt and the polyethylene terephthalate melt were weighed with a gear pump, introduced into a spin block kept at 262 ° C., and then the two polymer melt flows were combined to form a circular discharge hole. It is discharged at a rate of 1.0 g / min / hole from a rectangular spinneret of 20 cm × 120 cm in a grid arrangement, cooled with cooling air, and then compressed with compressed air using an air soccer ball under the cap. At high speed, a split type composite fiber was obtained.

  The pulled composite fiber was collected with a width of 1 m on a net conveyor together with an air flow as a web made of a peeled split type composite fiber having a 16-part multi-layer laminating type cross section. Subsequently, the obtained web was passed through a pair of upper and lower embossed calender rolls heated to 100 ° C. and lightly heat-bonded.

Then, the webs were overlapped by 8 layers and applied with an oil agent, and then entangled with a needle punch having a penetrate number of 1200 / cm ² to obtain a nonwoven fabric having a basis weight of 245 g / m ² and a thickness of 1.24 mm. Next, after being immersed in water, a separation treatment was performed at a speed of 6 m / min with a blown type divider, and then a shrink treatment was performed with a hot water bath at 70 ° C. to obtain an ultrafine fiber nonwoven fabric. Table 1 shows the physical properties of the obtained peelable split composite fibers and the ultrafine fiber nonwoven fabric.

[Examples 2 to 4, Comparative Examples 1 and 2]
Using the melt-mixed pellets of the modified polyester (a1) and polyalkylene glycol (b1) used in Example 1 and the polyethylene glycol flake powder (b2) having a molecular weight of about 19000, (a) and ( Exfoliated split-type composite fibers and ultrafine fiber nonwoven fabrics were obtained in the same manner as in Example 1 except that the addition weight ratio of b) was variously changed. Each physical property is shown together in Table 1.

  In Comparative Example 1, the modified polyester (a) was not added to nylon-6 (A) but only polyethylene glycol (b) was added. In Comparative Example 2, the modified polyester (a) and polyalkylene glycol (b) ), Only the pellets of the modified polyester (a1) alone were added to nylon-6 (A). Further, when the fiber was spun in the same manner as in Example 1 using 10% by weight of the modified polyester (a1) and 12% by weight of the polyalkylene glycol (b) with respect to the weight of the nylon-6 (A), the fiber was undivided because the interface was unclear. Met.

[Example 5]
As the modified polyester (a), a sulfonic acid group-containing modified polyester copolymer (a2) comprising 13 parts by weight of terephthalic acid, 2 parts by weight of sodium 5-sulfoisophthalate, 3 parts by weight of ethylene glycol, and 82 parts by weight of polyethylene glycol having a molecular weight of 4000 ) Was melted at 130 ° C. under vacuum, and polyethylene glycol (b1) having a molecular weight of about 19000 was added as polyalkylene glycol (b) to form a pellet. At that time, the mixing ratio of the modified polyester (a) and the polyalkylene glycol (b) was (a) :( b) = 4: 1. Using this mixture, a separation-dividing composite fiber and an ultrafine fiber nonwoven fabric were obtained in the same manner as in Example 1. Each physical property is shown together in Table 1.

[Example 6]
As the modified polyester (a), a sulfonic acid group-containing modified polyester copolymer (a3) comprising 133 parts by weight of terephthalic acid, 11 parts by weight of isophthalic acid, 6 parts by weight of sodium 5-sulfoisophthalate, and 48 parts by weight of ethylene glycol is prepared. And made into pellets. Using polyethylene glycol flake powder (b2) having a molecular weight of about 19000 as the polyalkylene glycol (b), mixing the modified polyester (a) and the polyalkylene glycol (b) with respect to nylon-6 in the same manner as in Example 1. The weight ratio was added so as to be (a) :( b) = 1.3: 3.7 to obtain a peelable split composite fiber and an ultrafine fiber nonwoven fabric. Each physical property is shown together in Table 1.

[Comparative Example 3]
Modified polyester (a ′) not containing a sulfonic acid group is a modified polyester not containing a sulfonic acid group comprising 17 parts by weight of terephthalic acid, 2 parts by weight of isophthalic acid, 5 parts by weight of ethylene glycol, and 75 parts by weight of polyethylene glycol having a molecular weight of 4000. A copolymer (a ′) was prepared and melted at 130 ° C. under vacuum, and then polyethylene glycol (b1) having a molecular weight of about 19000 was added as a polyalkylene glycol (b) to form a pellet. At that time, the mixing ratio of the modified polyester (a ′) and the polyalkylene glycol (b) was (a ′) :( b) = 4: 1. Using this mixture, a peelable split composite fiber and an ultrafine fiber nonwoven fabric were obtained in the same manner as in Example 1. Each physical property is shown together in Table 1.

[Example 7]
After impregnating the ultrafine fiber nonwoven fabric obtained in Example 1 with a polyurethane emulsion solution of 18% by weight, applying heat with 90 ° C. steam, immersing it in water to coagulate the polyurethane, thoroughly washing and removing it, then 120 ° C. To obtain impregnated substrate-1. Next, a release liquid (on top, a blended liquid prepared by adding 5 parts of a thickener and a colorant (black) to 100 parts of a 33% aqueous dispersion of polyurethane while stirring to adjust the viscosity to 8000 mPa · s (CP)) It was coated at a basis weight of 90 g / m ² and dried at a temperature of 70 ° C. for 2 minutes and at 110 ° C. for 2 minutes to form a polyurethane colored film.

Furthermore, on the surface, a mixed liquid in which 100 parts of a water-dispersible polyurethane adhesive (45% concentration) was mixed with 5 parts of a colorant (black) and a thickener to adjust the viscosity to 5000 mPa · s (CP). The coating weight was 150 g / m ² . Next, after drying at a temperature of 90 ° C. for 2 minutes, the substrate for artificial leather was superposed and passed through a roll with a gap of 0.6 mm on the surface of a heated cylinder at a temperature of 110 ° C. and pressure bonded. Then, after leaving for 2 days in an atmosphere at a temperature of 60 ° C., the release paper was peeled off to obtain artificial leather.

The resulting artificial leather has a thickness of 1.40 mm, an apparent density of 0.49 g / m ³ , a bending resistance of 1.38 g / cm corresponding to the degree of flexibility, and exhibits a high flexibility despite being high density. The texture was also excellent.

The schematic diagram which showed the fiber cross section of the split type composite fiber of this invention.

Explanation of symbols

1. Polyamide polymer component
2. Polyester polymer component

Claims (9)

  A modified polyester in which at least one component of two or more fiber-forming components constituting the split-type conjugate fiber is mainly a polyamide polymer (A), and at least one component of the two or more fiber-forming components has a sulfonate group. A split type composite fiber comprising a component (a) and a polyalkylene glycol component (b).   The split type composite fiber according to claim 1, wherein the modified polyester component (a) is present in the polyamide polymer (A) as a melt or a granular material.   The split type composite fiber according to claim 1 or 2, wherein the polyamide-based polymer (A) contains 3 to 20% by weight of the total amount of the modified polyester component (a) and the polyalkylene glycol component (b).   The split-type composite fiber according to any one of claims 1 to 3, wherein the fiber moldable components constituting the split-type composite fiber are a polyamide polymer (A) and a polyester polymer (B).   The split type composite fiber according to claim 4, wherein the polyester polymer (B) contains a modified polyester component (a) having a sulfonate group.   The split-type conjugate fiber according to any one of claims 1 to 5, wherein the fineness of the split-type conjugate fiber is 0.15 to 10 dtex.   The split-type composite fiber according to any one of claims 1 to 6, wherein the fineness of each fiber-forming component constituting the split-type composite fiber is 0.01 to 0.35 dtex.   An ultrafine fiber nonwoven fabric obtained by interlacing and dividing the split type composite fiber according to any one of claims 1 to 7.   A base material for artificial leather, wherein the ultrafine fiber nonwoven fabric according to claim 8 is impregnated with a polymer elastic body.

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